This invention relates to a method for the continuous production of sails for sailing vessels and more particularly to the production of laminated molded sails.
Conventional modern sails for sailing vessels are not flat but have a three dimensional foil shape. Most sails up to the present time have been made from flat panels of woven cloth, cloth and film laminates, or film laminates reinforced with yarns or scrim. The flat panels are first cut into a predetermined shape, and the panels are joined together along adjacent edges. In a process called broadseaming, one or both of the adjacent edges of the panels may be curved, such that the subsequent seaming results in an approximate three dimensional shape.
The construction of a sail on a static mold is well known and is described in Wagner EP patent 056,657 and in Gardiner U.S. Pat. No. 2,565,219 and Baudet U.S. Pat. No. 5,097,784.
The Baudet patent discloses a one piece three dimensional sail which is seamless and paneless. The sail is constructed on a convex mold having a three dimensional shape, with the shape of the mold being adjustable to the desired shape of the sail. A first layer of film is placed on the mold, reinforcing yarns are applied with an overhead gantry together with adhesive, and a final layer of film is applied. The laminate is then heated under pressure to bond the adhesives and to cause the laminate to permanently assume the shape of the mold. Sails of this nature are currently being marketed by North Sails under the trademark "3DL" and have achieved substantial commercial success.
While the sail described in U.S. Pat. No. 5,097,784 has superior qualities in comparison to conventional sails made from seamed individual panels, the process for making the sail is labor intensive and time consuming. The mold must be large enough to accommodate a variety of sizes of sails, and only a single sail can be produced on the mold at one time. Also, the mold itself is a complicated and expensive structure, and the process have many variables which require careful control.